A set of tools for building postgreSQL distributed databases in biomedical environment

PostgreSQL is an advanced Object-Relational DBMS supporting SQL constructs and accessible with standard protocols. Its object-oriented features qualify it for managing biomedical data and it is freely available to the community via the open-source philosophy. Unfortunately the current available version does not support any database distribution feature. The aim of the present work was to develop specific procedures In order to extend original potentials of PostgreSQL ORDBMS and make it able to manage distributed databases by means of asynchronous replication. Particular attention was devoted to conflict resolution rules, including several procedures with different degrees of restrictiveness and even giving the end user the possibility to write user-defined conflict resolution procedures. The replication system was tested at the IRCCS "E, Medea", an Italian Scientific and clinical research Institute spread over 5 sites In different geographical locations. The testing system was developed with the purpose to make clinical data collected by Epileptology Units in each site available to all branches, without having to care for their physical distribution. The proposed replica procedures manage only traditional (non-binary) data types because of the very different storage model of large objects. Since large objects are very common for treatment and storage of biomedical data, the authors are currently working on an improved version of the replica engine that allows large objects to be replicated.